package XieCheng;

import java.util.*;

/**
 * Description：
 * Author: zhangc
 * Date：2017/9/21 19:39
 */
public class HelloWorld {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String next = scanner.nextLine().trim();
        char[] chars = next.toCharArray();

        LinkedHashSet<Character> set = new LinkedHashSet<>();
        for (int i = 0; i < chars.length; i++) {
            set.add(chars[ i ]);
        }
        StringBuilder stringBuilder = new StringBuilder();
        for (Character character : set) {
            stringBuilder.append(character);
        }
        System.out.println(stringBuilder.toString());
    }

}

